Open packing number for some classes of perfect graphs

Let $G$ be a graph with the vertex set $V(G)$. A subset $S$ of $V(G)$ is an open packing set of $G$ if every pair of vertices in $S$ has no common neighbor in $G.$ The maximum cardinality of an open packing set of $G$ is the open packing number of $G$ and it is denoted by $\rho^o(G)$. In this paper, the exact values of the open packing numbers for some classes of perfect graphs, such as split graphs, $\{P_4, C_4\}$-free graphs, the complement of a bipartite graph, the trestled graph of a perfect graph are obtained.